Method: 1. Heat 250 ml of water in a pan over medium flame. 2. Add the sugar and stir well until fully dissolved. 3. Bring to a boil and remove from flame. 4. Allow it to cool. 5. Transfer to a blender with the blackberries. 6. Blend well until smooth and strain into a large pitcher. 7. Add the remaining water and lemon juice. 8. Stir well. 9. Pour into individual serving glasses over ice cubes. 10. Garnish with mint leaf, lemon slice and a blackberry.